INITIAL SUSCEPTIBILITY OF FERRIMAGNETIC MATERIALS AND TOPOGRAPHY OF DOMAIN WALLS

Observations are reported, that ferrimagnetic materials which are identical in their fundamental properties (composition, Ms, Tc, λs) as well as in their granular structure (porosity, size, and shape of grains) can present very different thermal spectra of initial susceptibility. This behaviour is found to be general for the many compositions studied. The proposed interpretation is based on the existence of different degrees of wall continuity accross the grain boundaries. It is suggested that the degree of wall continuity is associated with the relative crystallographic axes orientation of the grains. The experimental results of the frequency spectra of intial susceptibility support this hypothesis. It is also observed that the hysteresis of thermal spectra is quite general and this in turn can be related to the wall topography. Copyright © 1969 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim